I. Technical Field
The present invention generally relates to the field of enterprise path management. More particularly, the invention relates to systems and methods for disabling an array port for an enterprise.
II. Background Information
Enterprise storage systems store data in large-scale environments and differ from consumer storage systems in both the size of the environment and the types of technologies that store and manage the data. A large-scale environment that stores data is typically referred to as a storage area network (SAN). SANs are commonly used in enterprise storage systems to transfer data between computer systems and storage devices. A typical SAN provides a communication infrastructure, including physical connections between devices, and a management layer, which organizes the connections, storage devices, and computer systems.
In a SAN environment, one or more servers provide services to other systems (e.g., clients) over the network. Servers in a SAN environment are typically referred to as hosts. Each host connects to the SAN via one or more host bus adapters. In the case of a Fibre Channel SAN, the hosts may use special Fibre Channel host bus adapters and optical fiber for connections between devices.
An enterprise storage system may include multiple disk drives that combine to form a disk array. A typical disk array includes a disk array controller, a cache, disk enclosures, and a power supply. Examples of disk arrays include the SYMMETRIX Integrated Cache Disk Array System the CLARIION Disk Array System, both available from EMC Corporation of Hopkinton, Mass. A disk array controller is a piece of hardware that provides storage services to computer systems that access the disk array. The disk array controller may attach to a number of disk drives that are located in the disk enclosures. For example, the disk drives may be organized into RAID groups for efficient performance. RAID (redundant array of inexpensive disks) is a system that uses multiple disk drives that share or replicate data among the drives. Accordingly, in a RAID system, instead of identifying several different hard drives, an operating system will identify all of the disk drives as if they are a single disk drive.
Disk array controllers connect to a SAN via a port. A port serves as an interface between the disk array controller and other devices in the SAN. Each disk array controller typically includes two or more ports. Disk array controllers may communicate with other devices using various protocols, such as the SCSI (Small Computer System Interface) command protocol over a Fibre Channel link to the SAN. In the SCSI command protocol, each device is assigned a unique numerical identifier, which is referred to as a logical unit number (LUN). Further, communication using the SCSI protocol is said to occur between an “initiator” (e.g., a host) and a “target” (e.g., a disk drive) via a path. For example, a path may include a host bus adapter, an associated SCSI bus or Fibre Channel cabling, and a single port of a disk array controller.
Path management software is frequently used to manage SANs and, among other things, can detect load imbalances for disk array controllers in a SAN and can select alternate paths through which to route data. An example of path management software is EMC POWERPATH by EMC Corporation of Hopkinton, Mass.
When a disk array controller or port of a disk array controller needs maintenance, the disk array controller or port must be taken offline. Taking a disk array controller or port offline will cause input/output errors and path failures across a SAN for any hosts accessing logical units through the offline disk array controller or port. These errors are often difficult to diagnose and may cause unnecessary corrective actions to occur. It is instead preferred to take a disk array controller or port offline with respect to an enterprise before the disk array controller or port is placed in an offline state in the array. However, typical path management software does not provide functionality for disabling array controllers and array ports with respect to an entire enterprise. Therefore, conventional techniques are limited and suffer from one or more drawbacks.
In view of the foregoing, there is a need for improved systems and methods for disabling a port or an array controller.